Presenter: Peg Coleman

Format: MP4 Video file download
Includes: Video & Slides

Risk practitioners who contributed to the first issue of the technical journal Risk Analysis in 1981 recognized that risk is not a number, but a set of estimates with attendant uncertainty. Though the concept of uncertainty (what we don?t know) is easy to understand, quantifying uncertainty is complex, particularly because available scientific data are nearly always incomplete and ambiguous. Risk cannot generally (if ever) be calculated directly from the data available, and gaps in knowledge require use of assumptions to bridge data gaps. Biases may be imbedded in the selection of assumptions to bridge the gaps for risk assessments, rather than communicated transparently and objectively. Three simple questions are essential to properly frame communications of risk to all stakeholders, including not only technical and scientific experts, but especially the general public affected by decisions based on the risk assessment. These three questions (1. What can go wrong?; 2. How likely is it?; and 3. What are the consequences?) apply to a set of possible scenarios that might describe future hypothetical exposures, potential adverse effects, and costs and benefits associated with the set of scenarios selected by the risk assessment team or their managers. The professional organization Society for Risk Analysis (SRA) who publish the journal Risk Analysis advocate cycles of analysis and deliberation (analytic-deliberative process) to ensure that the public is appropriately engaged in discourse regarding the assumptions that may bias risk estimates, particularly when disagreements exist about the nature and magnitude of risk.

This session focuses on the exercise of analytic-deliberative process for the controversial assessments of risk for consumers of certified raw milk and pasteurized milk. Overviews of exposure assessment and dose-response assessment emphasize the knowledge gaps and the impact of assumptions that may bias existing microbial risk assessments for listeriosis in milk consumers. The available listeriosis risk assessments do not yet incorporate expanding knowledge of the healthy human microbiomes. Two concepts from the Human Microbiome Project that influence microbial risk, colonization resistance and dysbiosis, are introduced. These concepts challenge old dogma about microbial contributions to human health and disease that may mislead unwary stakeholders of risk assessments.